/Engine/Source/Editor/MaterialEditor/Public/MaterialEditingLibrary.h
Set the scalar (float) parameter value for a Material Instance
static bool SetMaterialInstanceScalarParameterValue ( [UMaterialInstanceConstant](API\Runtime\Engine\Materials\UMaterialInstanceConstant) * Instance, [FName](API\Runtime\Core\UObject\FName) ParameterName, float Value, EMaterialParameterAssociation Association )